Multi-species and multi-tissue methylation clocks for age estimation in toothed whales and dolphins

The development of a precise blood or skin tissue DNA Epigenetic Aging Clock for Odontocete (OEAC) would solve current age estimation inaccuracies for wild odontocetes. Therefore, we determined genome-wide DNA methylation profiles using a custom array (HorvathMammalMethyl40) across skin and blood samples (n=446) from known age animals representing nine odontocete species within 4 phylogenetic families to identify age associated CG dinucleotides (CpGs). The top CpGs were used to create a cross-validated OEAC clock which was highly correlated for individuals (r=0.94) and for unique species (median r=0.93). Finally, we applied the OEAC for estimating the age and sex of 22 wild Norwegian killer whales. DNA methylation patterns of age associated CpGs are highly conserved across odontocetes. These similarities allowed us to develop an odontocete epigenetic aging clock (OEAC) which can be used for species conservation efforts by provide a mechanism for estimating the age of free ranging odontocetes from either blood or skin samples. Todd Robeck and Zhe Fei et al. use DNA methylation profiling to develop an epigenetic clock to measure age in odontocete species, including toothed whales and dolphins. The clocks were highly accurate and represent a valuable tool to help in wildlife conservation efforts.

Automated summary

Researchers developed an epigenetic clock for odontocetes using DNA methylation profiling, allowing for accurate age estimation and identification of sex in wild individuals. This clock serves as a valuable tool for wildlife conservation efforts.